Please answer correctly I’ll mark you brainlist!

Find the equation of the line that goes through the points (4, –1) and (2, –5). use slope formula,equation,to find the slope of a line that passes through the points. m = use slope-intercept form, y = mx + b, to find the y-intercept (b) of the line. b = write the equation in slope-intercept form, y = mx + b.

What is the value of x when x + 7 = 21?

Find the amplitude of a sinusoidal function that models this temperature variation